78623681 has 2 divisors, whose sum is σ = 78623682. Its totient is φ = 78623680.

The previous prime is 78623647. The next prime is 78623687. The reversal of 78623681 is 18632687.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 71910400 + 6713281 = 8480^2 + 2591^2 .

It is an emirp because it is prime and its reverse (18632687) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78623681 - 2⁶ = 78623617 is a prime.

It is a super-2 number, since 2×78623681² = 12363366427979522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (78623687) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39311840 + 39311841.

It is an arithmetic number, because the mean of its divisors is an integer number (39311841).

Almost surely, 2^78623681 is an apocalyptic number.

It is an amenable number.

78623681 is a deficient number, since it is larger than the sum of its proper divisors (1).

78623681 is an equidigital number, since it uses as much as digits as its factorization.

78623681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 96768, while the sum is 41.

The square root of 78623681 is about 8866.9995488891. Note that the first 3 decimals coincide. The cubic root of 78623681 is about 428.4016395312.

The spelling of 78623681 in words is "seventy-eight million, six hundred twenty-three thousand, six hundred eighty-one".